The invention relates generally to the field of bonded polymeric fiber structures and, more particularly, to multi-component structures comprising a plurality of components, at least one of which is a three dimensional bonded fiber structure. Specifically, two or more components may be integrally formed into a single, substantially self-sustaining, three dimensional structure, in which at least one component is a three dimensional bonded fiber structure. This resultant structure may exhibit, in different components, different structural characteristics and resulting properties.
A fiber component and material used in a particular bonded fiber component may be tailored to specific applications. In particular, specific fiber types may be selected to provide a particular set of fluid manipulation properties and/or facilitate processing. For example, some fiber types may provide a higher surface energy that would facilitate wicking of a fluid. Other fiber types may provide bonding advantages. In some polymeric fiber components, a plurality of different fiber types may be used to provide a particular combination of characteristics.
The inclusion of a non-fibrous component in the integrally formed multi-component structure may provide additional benefits. For example, a permeable or impervious membrane may be included to provide particular fluid treatment properties. Similarly, non fibrous components may be included to provide additional structural, mechanical, filtering, or any other properties.
Bonded polymeric fiber components and structures have demonstrated distinct advantages for fluid storage and fluid manipulation applications, since such bonded fiber structures have been shown to take up ink of various formulations and controllably release it. A typical use for these components and structures may include use as nibs for writing instruments, ink reservoirs, wicks for a wide variety of devices and applications, depth filters, and other applications where the surface area and porosity characteristics of such components or structures are advantageous.
Additionally, fiber components and structures may find use in diverse medical applications, for example, to transport a bodily fluid by capillary action to a test site or diagnostic device. Other applications of fibrous products are as absorption reservoirs, products adapted to take up and simply hold liquid as in a diaper or incontinence pad. Still other applications of bonded fiber components and structures may be high temperature filtration elements. Characteristics beneficial to the application as a high temperature filtration element include a relatively high melting temperature, and the definition of a tortuous interstitial path effective for capturing of fine particulate matter when a gas or liquid is passed through the fiber filter.
As described in U.S. Pat. Nos. 5,607,766, 5,620,641, 5,633,082, 6,103,181, 6,330,883, and 6,840,692, each of which is incorporated herein by reference in its entirety, there are many forms of and uses for bonded fiber components and structures, as well as many methods of manufacture. In general, such bonded fiber components and structures are formed from webs of thermoplastic fibrous material comprising an interconnecting network of highly dispersed continuous fibers bonded to each other at points of contact. These webs can then be formed into substantially self-sustaining, three-dimensional porous components and structures. These components or structures may provide high surface areas and porosity, and may be formed in a variety of sizes and shapes.